Vapor permeation curable polyester resin coating compositions for flexible substrates

Abstract

Disclosed is a coating composition rapidly curable at room temperature in presence of a vaporous tertiary amine catalyst and possessing a flexibility sufficient for a zero-T bend on metal and a mar resistance of at least about 2,000 grams as borne by the edge of a nickel passed on said film. The coating composition is a phenolic-terminated-polyester and multi-isocyanate curing agent (at least about 10% aromatic isocyanate content) dispersed in a fugitive organic solvent, and a mar-resisting aid of an organic compound physically incompatible in said coating composition and having an effective chain length of at least about 12 carbon atoms. Application of the coating composition preferably is on a flexible substrate such as a thermoplastic substrate.

I claim: 
     
       1. A composite article comprising a flexible substrate having an adherent cured film of a curable coating composition thereon, said film at a thickness of between about 0.1 and 0.5 mils possessing a flexibility sufficient for a O-T bend on metal and a mar resistance of at least about 2000 gms as borne by the edge of a nickel passed over said cured film, said film being the cured residue of said coating composition after exposure to a vaporous tertiary amine catalyst, said coating composition comprising: (A) an aromatic hydroxyl-functional condensation product having an acid number of less than about 10 and made by condensing the following ingredients in the indicated molar proportions or double thereof except for the phenolic-functional carboxylic acid: (1) between about 1 and 2 moles of a C 2  -C 12  linear aliphatic dibasic acid,   (2) between about 1 and 2 moles of an ortho or meta aromatic dicarboxylic acid or anhydride thereof,   (3) between about 1 and 4 moles of a C 2  -C 6  alkylene glycol,   (4) between about 1 and 2 moles of a sterically hindered diol,   (5) between about 1 and 2 moles of a mono-epoxide or diol having a pendant C 8  -C 22  hydrocarbyl group, and   (6) between about 1 and 2 moles of a phenolic-functional carboxylic acid;     (B) a multi-isocyanate comprising: (1) between about 10 and 80 percent by weight of an aromatic multi-isocyanate, and   (2) between about 90 and 20 percent by weight of an aliphatic multi-isocyanate;     (C) a volatile oganic solvent for such condensation product and for said multi-isocyanate, and   (D) a mar-resisting agent of an organic compound physically incompatible in said coating composition and having an effective chain length of at least about 12 carbon atoms; the ratio of aromatic hydroxyl equivalents of said condensation product to the isocyanate equivalents of said multi-isocyanate being between about 1:1 and 1:1.7, said condensation product containing substantially no aliphatic hydroxyl groups, and said condensation product having a phenol functionality of at least 2.     
     
     
       2. The composite article of claim 1 wherein said condensation product is made by condensing: (1) between 1 and 2 moles of adipic acid,   (2) between 1 and 2 moles of isophthalic acid,   (3) between 1 and 4 moles of propylene glycol,   (4) between 1 and 2 moles of neopentyl glycol,   (5) between 1 and 2 moles of an epoxy-ester having pendant hydrocarbyl groups, and   (6) between 1 and 2 moles of a diphenolic-type acid.   
     
     
       3. The composite article of claim 1 or 2 wherein said diphenolic-type acid is represented by ##STR4## where R 1  is H or C 1  -C 8  alkyl group, and R 3  is a sigma bond or a C 1  -C 8  polymethylene group.   
     
     
       4. The composite article of claim 3 wherein said condensation product is made by condensing: (1) 2 moles of adipic acid,   (2) 1mole of isophthalic acid,   (3) 1 mole of propylene glycol,   (4) 2 moles of neopentyl glycol,   (5) 1 mole of said epoxy-ester, and   (6) 2 moles of said diphenolic-type acid.   
     
     
       5. The composite article of claim 3 wherein for said diphenolic acid, R 2  =CH 3 , and   R 3  ----CH 2  --CH 2  --.   
     
     
       6. The composite article of claim 1 wherein the proportion of said mar-resisting agent is between about 0.5% and 1.0% by weight and said agent is an ester of a C 12  -C 30  carboxylic acid. 
     
     
       7. The composite article of claim 1 wherein said solvent is a mixture of ketones, esters, and organic solvents. 
     
     
       8. The composite article of claim 1 wherein said flexible substrate is a thermoplastic substrate. 
     
     
       9. A flexible coated substrated prepared by the method which comprises: (I) applying said coating composition to said flexible substrate, said coating composition having a pot life of at least about 4 hours in an open pot and comprising: (A) an aromatic hydroxyl-functional condensation product having an acid number of less than about 10, having an aromatic hydroxyl-functionality of at least 2, and containing substantially no aliphatic hydroxyl groups, said condensation product made by condensing the following ingredients in the indicated molar proportions or double thereof except for the phenol-functional carboxylic acid: (1) between about 3 and 8 moles of a mixture of diols which include a sterically hindered diol, and a diol or mono-epoxide which provides a pendant C 8  -C 22  hydrocarbyl group; and   (2) between about 3 and 6 moles of a mixture of a linear aliphatic dibasic acid and an ortho or meta aromatic dicarboxylic acid, and a phenol-functional carboxylic acid having at least one carbon atom between said phenol group and said carboxyl group;     (B) a multi-isocyanate cross-linking agent comprising a mixture of between about 10% and 80% by weight of an aromatic multi-isocyanate and between about 90% and 20% by weight of an aliphatic multi-isocyanate, wherein the ratio of aromatic hydroxyl equivalents from said condensation product to the isocyanate equivalents of said multi-isocyanate ranges from between about 1:1 and 1:1.7;   (C) a volatile organic solvent for said condensation product and for said multi-isocyanate; and   (D) a mar-resisting agent of an organic long chain fatty compound physically incompatible in said coating composition and having an effective chain length of at least 12 carbon atoms;     (II) exposing said coated flexible substrate to a vaporous tertiary amine catalyst to rapidly cure said coating at about room temperature;   said cured coating having a film thickness of between about 0.1 and about 0.5 mils;   said cured film of said coating composition possessing a flexibility sufficient for a zero-T bend on metal and a mar resistance of at least about 2,000 grams as borne by the edge of a nickel passed over said cured film.   
     
     
       10. The flexible coated substrate of claim 9 wherein said condensation product is made by condensing the following ingredients or double thereof except for said phenol-functional carboxylic acid: (a) between about 1 and 2 moles of a C 2  -C 12  linear aliphatic dibasic acid,   (b) between about 1 and 2 moles of said ortho or meta dicarboxylic acid,   (c) between about 1 and 4 moles of a C 2  -C 6  alkylene glycol,   (d) between about 1 and 2 moles of said sterically hindered diol,   (e) between about 1 and 2 moles of said mono-epoxide or diol having a pendant C 8  -C 22  hydrocarbyl group, and   (f) between about 1 and 2 moles of said phenol-functional carboxylic acid.   
     
     
       11. The flexible coated substrate of claim 10 wherein said condensation product is made by condensing the following ingredients in the indicated molar proportions or double thereof except for said phenol-functional carboxylic acid: (a) between 1 and 2 moles of adipic acid,   (b) between 1 and 2 moles of isophthalic acid,   (c) between 1 and 4 moles of propylene glycol,   (d) between 1 and 2 moles of neopentyl glycol,   (e) between 1 and 2 moles of an epoxide of a C 8  -C 22  mono-olefin or a 1,2-glycol containing a C 8  -C 22  hydrocarbyl group, and   (f) between 1 and 2 moles of said phenol-functional carboxylic acid represented by ##STR5##  where R 1  is H or a C 1  -C 8  alkyl group, and R 3  is a sigma bond or a C 1  -C 8  polymethylene group.   
     
     
       12. The flexible coated substrate of claim 9 or 11 wherein said cured film on said flexible coated substrate is heat-embossed. 
     
     
       13. The flexible coated substrate of claim 9 or 11 wherein said substrate is thermoplastic. 
     
     
       14. The flexible coated substrate of claim 11 wherein said coating composition additionally contains between about 2.5% and 10% by weight of the non-volatile solids of a silica flatting agent having a mean particle size of about 3 microns.